A nearly homogeneous preparation of an extracellular serine esterase-protease produced by Bacillus subtilis 168 (trp-) has been obtained under conditions which prevent autolysis. The molecular weight, amino acid composition, and chemical nature of the carbohydrate moeity attached to this enzyme will be determined. A highly purified form of the intracellular serine protease has also been isolated and attempts will be made to determine its substrate specificity and to determine if it also is a glycoprotein. Experiments are now underway to determine the degree, if any, of protein turnover (meaning balanced degradation and synthesis) of individual proteins during sporulation. The method being used is two-dimensional electrophoresis (O'Farrell method) of cell-extracts prepared from cells labeled at different times with an amino acid bearing different isotopic tracers. In addition, in vivo experiments using various aldehyde protease inhibitors are being performed.